Methods and compositions for treating viral infections

ABSTRACT

The present invention provides compositions and methods for treating, preventing, and inhibiting viral replication, viral infections and viral diseases and disorders, comprising the use of artemisinin derivatives having anti-viral activity.

This application is a continuation of U.S. Ser. No. 14/394,973 filedOct. 16, 2014, which is a 35 U.S.C. §371 national phase entryapplication from PCT/IL2013/050335, filed on Apr. 17, 2013, anddesignating the United States, which claims the benefit of U.S.Provisional Application No. 61/625,701 filed on Apr. 18, 2012, which areincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention is directed to compositions and methods forinhibiting viral replication and treating viral infections, diseases anddisorders, comprising the use of artemisinin derivatives havinganti-viral activity.

BACKGROUND OF THE INVENTION

The compound artemisinin, also known as qinghaosu (III), is atetracyclic 1,2,4-trioxane occurring in Artemisia annua and is describedin U.S. Pat. No. 4,920,147 to McChesney et al. Artemisinin and itsderivatives dihydroartemisinin (DHA) (IV), artemether (V) and artesunate(VI) (FIG. 1) have been used primarily for the treatment of malaria, asdescribed in U.S. Pat. No. 6,306,896 to Scheiwe.

Chemical studies on artemisinin and its synthetic derivatives indicatethat a cause of instability is the facile opening of the trioxane moietyin artemisinin, or in its derivative dihydroartemisinin. Ring openingprovides the free hydroperoxide, which is susceptible to reduction.Removal of this group ensures destruction of drug activity with thereduction products being transformed into desoxo metabolites. In orderto render ring-opening less facile, the oxygen atom at C-10 can beeither removed to provide 10-deoxydihydroartemisinin, or replaced byother groups. This has provided the basis for the so-called “secondgeneration” compounds which are generally 10-deoxy artemisininderivatives. In addition, derivatives of artemisinin with a variety ofsubstituents at C-9 have also been prepared.

Artemisinin derivatives in which the oxygen atom at C-10 is replaced byan amine group have been produced. For instance, Yang et al. (Biorg.Med. Chem. Lett., 1995, 5, 1791-1794) synthesized ten new artemisininderivatives in which the oxygen atom at C-10 was replaced by —NHAr,where Ar represents a phenyl, 3-chlorophenyl, 4-chlorophenyl,3-bromophenyl, 4-bromophenyl, 4-iodophenyl, 4-methylphenyl,4-methoxyphenyl, 3-carboxylphenyl or 4-carboxylphenyl group. Thesecompounds were tested for in vivo activity against the K173 strain ofPlasmodium berohei and were found to be active.

U.S. Pat. No. 6,984,640 and United States patent application2005/0119232 disclose certain C-10 substituted derivatives ofartemisinin that are disclosed to be effective in the treatment ofdiseases caused by infection with a parasite of the genera Plasmodium,Neospora or Eimeria, especially Plasmodium falciparum, Neospora caninumand Eimeria tenella, which cause malaria, neosporosis and coccidiosis,respectively. The disclosed compounds are of the general formula I:

or a salt thereof, in which Y represents a halogen atom, an optionallysubstituted cycloalkyl, aryl, C-linked heteroaryl or heterocyclylalkylgroup or a group —NR¹R²; where R¹ represents a hydrogen atom or anoptionally substituted alkyl, alkenyl or alkynyl group; R² represents anoptionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl oraralkyl group; or R¹ and R² together with the interjacent nitrogen atomrepresent an optionally substituted heterocyclic group or an amino groupderived from an optionally substituted amino acid ester; for use in thetreatment and/or prophylaxis of a disease caused by infection with aparasite.

Artemisinin derivatives, artemisone and especially artemiside have beenshown by Dunay et al. (Antimicrob Agents Chemother. 2009, 53(10),4450-4456) to display enhanced inhibition of Toxoplasma gondii, and byGuo et al. (Antimicrob Agents Chemother. 2012, 56(1), 163-173) to have apronounced effect on Plasmodium falciparum. Artemisone differs fromcurrently used clinical artemisinins in that it does not elicitneurotoxicity in preclinical in vitro and in vivo screens. In a pilottolerability test, treatment of male rats with artemisone at 50 mg/kgfor 14 days had no effect as compared to controls. Studies involvingproliferation of human endothelial cells and generation of new vessels,indicate that artemisone is significantly less anti-angiogenic thandihydroartemisinin, suggesting that it might be safer to use artemisoneduring pregnancy (D'Alessandro et al., Toxicology, 2007, 241, 66-74).Newer polar derivatives including the urea derivative RW177 have alsobeen shown to have sub-nanomolar activity against the malarial parasite(see FIG. 1 for the structures of the derivatives).

U.S. Pat. No. 6,649,647 to one of the inventors of the presentinvention, discloses compounds containing a trioxane moiety, especiallycertain artemisinin derivatives, which have cytotoxic and anti-tumoractivity and their use in the treatment of cancer. Some of thesecompounds comprise a ligand which is capable of binding to a nucleicacid and a group containing a trioxane moiety which is capable of actingas source of free radicals which are capable of chemically interactingwith a nucleic acid. Processes for the preparation of such compounds andpharmaceutical compositions containing such compounds are also provided.

Viral infections account for a very large fraction of infectious diseasemortality and morbidity worldwide. Cytomegalovirus (CMV), for example, abeta herpesvirus, is a major cause of morbidity and mortality inimmunocompromised individuals including AIDS patients and recipients ofhematopoietic stem cell transplantation (HSCT) or solid organtransplants. CMV is also the leading cause of congenital infection,affecting ˜1% of live births, with resultant neurological damage andloss of hearing. Despite the considerable public health burden ofcongenital CMV, no established prenatal antiviral treatments areavailable.

In a transplantation setting, the widespread use of preventive antiviraltherapy has reduced the occurrence of early CMV disease; however, thedevelopment of late disease is increasingly recognized. Preventiveantiviral strategies include (a) preemptive therapy in patients whobecome positive for CMV antigen or CMV DNA in the blood aftertransplantation and (b) universal prophylaxis initiated in all at-riskpatients at the time of engraftment and continued until 100 days aftertransplantation.

All currently available anti-CMV drugs, including ganciclovir, foscarnetand cidofovir, target the viral DNA polymerase. Although these drugs areeffective, their use is limited by toxicity, low oral bioavailability,high cost, and teratogenicity. Additionally, prolonged or repeatedantiviral treatment may lead to the development of drug resistance andoccasionally cross-resistance to multiple drugs.

Artemisinin derivatives have been suggested for the treatment of viralinfections. United States patent application 2008/0161324 suggests thatartemisinins may be useful in combination with other agents in treatingviral diseases. Artesunate has been shown to inhibit the replication ofcytomegalovirus (CMV) (Efferth et al., J. Mol. Med., 2002, 80(4),233-242) and has been used to treat CMV infection (Shapira et al., Clin.Infect. Dis., 2008, 46(9), 1455-1457).

None of the above references discloses or suggests use of 10-alkylaminoartemisinin derivatives in treating viral infections or diseasesresulting therefrom.

Thus, there is a clear need for effective and safe, anti-CMV drugs withhigh oral bioavailability. In addition, there remains a critical andunmet medical need for new therapeutic modes of treating viralinfections.

SUMMARY OF THE INVENTION

The present invention provides compositions and methods for treating,attenuating, or inhibiting viral replication, viral infections, andviral diseases and disorders, comprising the use of artemisininderivatives having anti-viral activity.

The present invention is based in part on the unexpected finding thatseveral derivatives of artemisinin provide enhanced efficacy in treatingCMV, either alone or in combination with other anti-viral drugs. Withoutbeing bound by any theory or mechanism of action, the artemisininderivatives of the present invention are capable of inhibiting immediateearly (IE) gene expression of human CMV virus.

In one embodiment, the present invention provides a method for treatinga viral infection in a subject in need thereof, the method comprisingthe step of administering to the subject a pharmaceutical compositioncomprising a therapeutically effective amount of a compound havinganti-viral activity of formula I:

-   -   or a salt or a solvate thereof, wherein Y represents a group        —NR¹R²; wherein either    -   (i) R¹ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl or alkynyl group; and R² represents an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   (ii) R¹ and R² together with the interjacent nitrogen atom        represent a heterocyclic group or an amino group derived from an        optionally substituted amino acid ester; or    -   (iii) R¹ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and        R² represents an —X(═Z)-A group, wherein    -   X represents a carbon atom, a sulfur atom, a sulfoxide group        S═O, or a group PR³, P—O—R³ or P—N(R⁴)—R³, where R³ and R⁴ each        independently represent a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   Z represents an oxygen atom, a sulfur atom or a group NR⁵, where        R⁵ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and    -   A represents a hydrogen atom or an optionally substituted alkyl,        alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group, or a group        selected from N(R⁶)₂, NHNH₂, NR⁶NHR⁶, NR⁶N(R⁶)₂, OR⁶, SR⁶,        10α-dihydroartemisinyl, OR⁷ and NR⁶R⁷, where each R⁶        independently represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group, and R⁷ represents a bond attached as a substituent to R⁵        or R¹ which together with the interjacent groups represent an        optionally substituted heterocyclic group.

Each possibility represents a separate embodiment of the presentinvention.

In some embodiments, the present invention provides a pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundhaving anti-viral activity of formula I as defined herein, for use intreating a viral infection.

In another embodiment, the present invention provides the use of acompound having anti-viral activity of formula I as defined herein, inthe preparation of a medicament for treating a viral infection.

In one embodiment, the anti-viral activity of the compound of formula Ias defined herein is an anti-cytomegalovirus activity. In specificembodiments, the compound having anti-cytomegalovirus activity of thepresent invention inhibits the expression of IE genes.

In certain embodiments, the viral infection is a herpesvirus infection.In additional embodiments, the herpesvirus is selected from herpessimplex virus (HSV) and Epstein-Barr virus (EBV). Each possibilityrepresents a separate embodiment of the present invention. In otherembodiments, the viral infection is a flavivirus infection. In specificembodiments, the flavivirus is Bovine Viral Diarrhea virus (BVDV). Infurther embodiments, the viral infection is hepatitis B virus (HBV)infection or hepatitis C virus (HCV) infection. Each possibilityrepresents a separate embodiment of the present invention. In anexemplary embodiment, the viral infection is a cytomegalovirusinfection, in particular human cytomegalovirus infection. In specificembodiments, the cytomegalovirus is a strain resistant to knownanti-viral drugs. In other embodiments, the pharmaceutical compositionof the present invention is effective in cases of congenital infection.In certain embodiments, the pharmaceutical composition of the presentinvention is effective in treating, attenuating or suppressing CMVinfection in immunosuppressed patients including, in particular,transplantation recipients.

In some embodiments, the present invention provides a method forsuppressing viral replication, the method comprising the step ofadministering to a subject in need thereof a pharmaceutical compositioncomprising a therapeutically effective amount of a compound havinganti-viral activity of formula I:

-   -   or a salt or a solvate thereof, wherein Y represents a group        —NR¹R²; wherein either    -   (i) R¹ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl or alkynyl group; and R² represents an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;

(ii) R¹ and R² together with the interjacent nitrogen atom represent aheterocyclic group or an amino group derived from an optionallysubstituted amino acid ester; or

-   -   (iii) R¹ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and        R² represents an —X(═Z)-A group, wherein    -   X represents a carbon atom, a sulfur atom, a sulfoxide group S═O        or a group PR³, P—O—R³ or P—N(R⁴)—R³, where R³ and R⁴ each        independently represent a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   Z represents an oxygen atom, a sulfur atom or a group NR⁵, where        R⁵ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and    -   A represents a hydrogen atom or an optionally substituted alkyl,        alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group, or a group        selected from N(R⁶)₂, NHNH₂, NR⁶NHR⁶, NR⁶N(R⁶)₂, OR⁶, SR⁶,        10α-dihydroartemisinyl, OR⁷ and NR⁶R⁷, where each R⁶        independently represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group, and R⁷ represents a bond attached as a substituent to R⁵        or R¹ which together with the interjacent groups represent an        optionally substituted heterocyclic group.

Each possibility represents a separate embodiment of the presentinvention.

In particular embodiments, the method of suppressing viral replicationis an ex-vivo method comprising suppressing viral replication in a cellor in an organ culture.

In other embodiments, the present invention provides a pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundhaving anti-viral activity represented by the structure of formula I asdefined herein, for use in suppressing viral replication.

In various embodiments, the present invention provides the use of acompound having anti-viral activity of formula I as defined herein, inthe preparation of a medicament for suppressing viral replication.

In one embodiment, the anti-viral activity of the compound of formula Ias defined herein is an anti-cytomegalovirus activity. In specificembodiments, the compound having anti-cytomegalovirus activity of thepresent invention inhibits the expression of IE genes.

In certain embodiments, the viral replication is a herpesvirusreplication. In other embodiments, the viral replication is a flavivirusreplication. In one embodiment, the viral replication is acytomegalovirus replication, in particular human cytomegalovirusreplication. In specific embodiments, the cytomegalovirus is a strainresistant to known anti-viral drugs.

In some embodiments, the compound having anti-viral activity of thepresent invention is represented by the structure of formula VII:

wherein R¹ and R² together with the interjacent nitrogen atom representa non-aromatic heterocyclic group.

In some embodiments, the compound having anti-viral activity of thepresent invention is10α-(4′-(S,S-dioxothiomorpholin-1′-yl)-10-deoxo-10-dihydroartemisin,represented by the structure of formula VIII:

In further embodiments, the compound having anti-viral activity of thepresent invention is represented by the structure of formula IX:

In other embodiments, the compound having anti-viral activity of thepresent invention is represented by the structure of formula X:

-   -   wherein R¹ represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   X represents a carbon atom, a sulfur atom, a sulfoxide group S═O        or a group PR³, P—O—R³ or P—N(R⁴)—R³ where R³ and R⁴ each        independently represent a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   Z represents an oxygen atom, a sulfur atom or a group NR⁵ where        R⁵ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and    -   A represents a hydrogen atom or an optionally substituted alkyl,        alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group, or a group        selected from N(R⁶)₂, NHNH₂, NR⁶NHR⁶, NR⁶N(R⁶)₂, OR⁶, SR⁶,        10α-dihydroartemisinyl, OR⁷ and NR⁶R⁷, where each R⁶        independently represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group, and R⁷ represents a bond attached as a substituent to R⁵        or R¹ which together with the interjacent groups represent an        optionally substituted heterocyclic group.

In further embodiments, the compound having anti-viral activity of thepresent invention is represented by the structure of formula X, whereinR¹ represents a hydrogen atom or an optionally substituted alkyl,alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; X represents acarbon atom, a sulfur atom, or a sulfoxide group S═O; Z represents anoxygen atom or a sulfur atom; and A represents a N(R⁶)₂, NHNH₂, NR⁶NHR⁶,or NR⁶N(R⁶)₂ group, where each R⁶ independently represents a hydrogenatom or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl,aryl or aralkyl group.

In other embodiments, the compound having anti-viral activity of thepresent invention has an aqueous solubility at pH 7.2 greater than 40mg/L. In some embodiments, the compound having anti-viral activity ofthe present invention has a log P in the range of about 2.0-3.0. Inparticular embodiments, the compound having anti-viral activity of thepresent invention is incapable of being substantially converted in vivoto dihydroartemisinin.

In one embodiment, the pharmaceutical composition of the presentinvention further comprises a pharmaceutically acceptable carrier orexcipient.

In various embodiments, the pharmaceutical composition of the presentinvention is suitable for administration via a route selected from thegroup consisting of oral, rectal, intramuscular, subcutaneous,intravenous, inrtaperitoneal, intranasal, intraarterial, intravesicle,intraocular, transdermal and topical. Each possibility represents aseparate embodiment of the present invention.

According to some aspects and embodiments, the pharmaceuticalcomposition of the present invention is in the form selected from thegroup consisting of tablets, pills, capsules, pellets, granules,powders, lozenges, sachets, cachets, elixirs, suspensions, dispersions,emulsions, solutions, syrups, aerosols, ointments, soft and hard gelatincapsules, suppositories, sterile injectable solutions, and sterilepackaged powders. Each possibility represents a separate embodiment ofthe present invention.

In additional embodiments, the compound having anti-viral activity ofthe present invention is co-administered in combination with at leastone other anti-viral drug. Exemplary and non-limiting embodimentsinclude the co-administration of the compound having anti-viral activityof the present invention with an anti-viral drug selected from the groupconsisting of ganciclovir, valganciclovir, foscarnet, cidofovir,acyclovir and valacyclovir. Each possibility represents a separateembodiment of the present invention.

In particular embodiments, the compound having anti-viral activity ofthe present invention and the at least one other anti-viral drugtogether provide a therapeutic anti-viral effect which is at leastadditive.

In further embodiments, co-administration of the compound havinganti-viral activity of the present invention and the at least one otheranti-viral drug is performed in a regimen selected from a singlecombined composition, separate individual compositions administeredsubstantially at the same time, and separate individual compositionsadministered under separate schedules. Each possibility represents aseparate embodiment of the present invention.

In yet other embodiments, the present invention provides a method oftreating a viral infection having oncomodulatory activity associatedwith the development of a tumor in a subject in need thereof, the methodcomprising the step of administering to the subject a pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundhaving anti-viral activity of formula I as defined herein.

In additional embodiments, provided herein is a pharmaceuticalcomposition comprising a therapeutically effective amount of a compoundhaving anti-viral activity of formula I as defined herein, for use intreating a viral infection having oncomodulatory activity associatedwith the development of a tumor.

In further embodiments, the present invention provides the use of acompound having anti-viral activity of formula I as defined herein, inthe preparation of a medicament for treating a viral infection havingoncomodulatory activity associated with the development of a tumor.

In particular embodiments, the tumor is glioblastoma associated withcytomegalovirus infection. In another embodiment, the tumor is coloncancer or prostate cancer associated with cytomegalovirus infection. Inother embodiments, the tumor is Burkitt's lymphoma associated withEpstein Barr Virus (EBV) infection. In another embodiment, the tumor isHodgkin's lymphoma associated with EBV infection. In another embodiment,the tumor is post transplantation lympho-proliferative disorder (PTLD)associated with EBV infection. In yet another embodiment, the tumor isnasopharyngeal carcinoma associated with EBV infection. Each possibilityrepresents a separate embodiment of the present invention.

Other objects, features and advantages of the present invention willbecome clear from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Molecular structures of several artemisinin derivatives.

FIGS. 2A-2B: FIG. 2A. Artemisone dose response curve, showing inhibitionof CMV plaque formation following incubation with artemisone. ArtemisoneIC₅₀ value for this assay was 1.2 μM. FIG. 2B. Artemisone dose responsecurve, showing inhibition of CMV DNA accumulation following incubationwith artemisone.

FIGS. 3A-3B: FIG. 3A. Artesunate dose response curve, showing inhibitionof CMV plaque formation following incubation with artesunate. ArtesunateIC₅₀ value for this assay was 15 μM. FIG. 3B. Artesunate dose responsecurve, showing inhibition of CMV DNA accumulation following incubationwith artesunate.

FIG. 4: Immunofluorescence microscopy of the expression of CMV immediateearly (IE) and early-late (pp65) viral genes 24 and 72 hours postinfection (hpi).

FIGS. 5A-5B: FIG. 5A. HCMV IE antigen-positive cells in controluntreated infected cells versus drug-treated infected cells. FIG. 5B.HCMV pp65 antigen-positive cells in control untreated infected cellsversus drug-treated infected cells. Antigen-positive cells incontrol-untreated infected cells are presented as 100% for comparison.

FIGS. 6A-6F: Histopathological analysis of HCMV infected and uninfecteddecidual organ cultures. FIGS. 6A-6B. H&E stained sections (5 micron) ofuninfected decidual cultures prepared upon institution and at 8 days ofculture. Arrows point to the surface epithelium of the decidua. FIGS.6C-6D. Two different sections of cultures infected with HCMV strain PT30(10⁴ PFU/well), obtained at 6 dpi and subjected to H&E staining. Blackarrows indicate infected cells with “owl's eye” inclusion bodies; whitearrows indicate granular cytoplasmic inclusions; and black arrowheadsindicate irregular hyperchromatic nuclei. FIGS. 6E-6F. Sections ofcultures infected with HCMV strain PT30 (10⁴ PFU/well), obtained at 6dpi and subjected to immunohistochemical analysis for viralimmediate-early (IE) (showing nuclear staining) and early-late (pp65)(showing mainly cytoplasmic staining) proteins.

FIGS. 7A-7D: HCMV infection kinetics in decidual cultures. Decidualorgan cultures were infected with HCMV (10⁴ PFU/well). Images of strainPT30-infected cells in live tissues as detected by confocal microscopyat: FIG. 7A. Mock-infected cells; FIG. 7B. Day 2; FIG. 7C. Day 3; andFIG. 7D. Day 5.

FIG. 8: HCMV infection kinetics in decidual cultures. Viral DNAaccumulation in tissue lysates following infection with the indicatedviral strains, normalized by RNase P gene DNA copies. PT30: ♦; TB40/E:▪; AD169: Δ; and CI851: x.

FIG. 9: Cellular tropism of HCMV in infected decidual cultures. At 10dpi, frozen sections were prepared from decidual cultures infected withHCMV strain TB40/E expressing UL83 (pp65)-fused GFP, stained withmonoclonal antibodies against the indicated cell types, andcounterstained with DAPI to visualize the cell nuclei. Colocalization ofthe virus (marked by GFP) with specific cell markers was analyzed byconfocal microscopy. Arrows point to cells exhibiting colocalization,infected cells with no colocalization with the specific cellular marker;and stained uninfected cells. CK7, cytokeratin 7; vWF, von Willebrandfactor; Vim, vimentin.

FIG. 10: Inhibition of HCMV infection in decidual organ cultures byantiviral drugs (GCV: ; ACV: ▪). The results are expressed as apercentage of the amount of normalized HCMV DNA present in untreatedcultures±standard error. The error bars are not readily visible due tothe low values for standard error. Significant differences were foundbetween treated and untreated decidual cultures (P<0.05 by thetwo-tailed paired t test).

FIGS. 11A-11B: Neutralization and post adsorption inhibition of HCMVinfection in decidual organ cultures by HCMV hyper immune globulins(HIG). FIG. 11A. The indicated dilutions of HCMV HIG were incubated with10⁵ PFU of HCMV strain TB40/E for 1 hour prior to infection, in order toexamine viral neutralization. FIG. 11B. The indicated dilutions of HCMVHIG were added to the media of infected decidual cultures (10⁵ PFU/well)following extensive washing of the infected tissues at 24 hours postadsorption. Viral DNA in decidual tissue lysates was quantitated at 8dpi, and values were normalized by RNase P DNA copies. The results areexpressed as a percentage of the amount of normalized HCMV DNA presentin untreated cultures. Asterisks indicate significant differencesbetween treated and untreated decidual cultures (P<0.05 by thetwo-tailed paired t test).

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides compositions and methods for treating,preventing, attenuating, and inhibiting viral replication, viralinfections and viral diseases and disorders, comprising the use ofartemisinin derivatives having anti-viral activity, particularlyanti-CMV activity.

HCMV gene expression occurs through a highly coordinated cascade ofevents involving three general classes of viral genes: immediate early(IE; mainly IE1 and IE2) genes, delayed-early genes, including mainlygenes playing roles in viral DNA synthesis, and late viralgenes-encoding the virion structural components. Although thereplication cycle of HCMV is slow, requiring 48 to 72 hours to initiatethe release of progeny, the expression of IE gene products startsimmediately after viral entry and can be clearly detected at 24 hourspost infection. Viral functions which are expressed early, playregulatory roles later in infection. The switch from early phase to latephase is delayed until 24 to 36 hours post infection, and occurs uponviral DNA synthesis, with maximal levels of late gene expression presentat 72 to 96 hours post infection.

All currently approved anti-HCMV drugs, including ganciclovir, inhibitthe viral DNA polymerase, and thus do not inhibit IE gene expression,but rather inhibit late gene expression.

The present invention is based in part on the unexpected finding thatseveral 10-amino artemisinin derivatives are capable of blocking earlysteps as well as late steps of HCMV replication. Surprisingly, thecompounds of the present invention were shown to effectively inhibit theexpression of viral IE genes, which are the first genes to be expressedpost infection. The ability to inhibit early gene expression provides asignificant advantages over the hitherto known anti-viral agents whichonly affect late viral gene expression.

The present invention thus provides a method for treating a viralinfection in a subject in need thereof, the method comprising the stepof administering to the subject a therapeutically effective amount of acompound having anti-viral activity of formula I:

-   -   or a salt or a solvate thereof, wherein Y represents a group        —NR¹R², thereby treating a viral infection in a subject.

In some aspects and embodiments, R¹ represents a hydrogen atom or anoptionally substituted alkyl, alkenyl or alkynyl group; and R²represents an optionally substituted alkyl, alkenyl, alkynyl,cycloalkyl, aryl or aralkyl group.

In other aspects and embodiments, R¹ and R² together with theinterjacent nitrogen atom represent a heterocyclic group or an aminogroup derived from an optionally substituted amino acid ester.

In yet other aspects and embodiments, R¹ represents a hydrogen atom oran optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl oraralkyl group; and R² represents an —X(═Z)-A group, wherein

-   -   X represents a carbon atom, a sulfur atom, a sulfoxide group        S═O, or a group PR³, P—O—R³ or P—N(R⁴)—R³, where R³ and R⁴ each        independently represent a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   Z represents an oxygen atom, a sulfur atom or a group NR⁵, where        R⁵ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and    -   A represents a hydrogen atom or an optionally substituted alkyl,        alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group, or a group        selected from N(R⁶)₂, NHNH₂, NR⁶NHR⁶, NR⁶N(R⁶)₂, OR⁶, SR⁶,        10α-dihydroartemisinyl, OR⁷ and NR⁶R⁷, where each R⁶        independently represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group, and R⁷ represents a bond attached as a substituent to R⁵        or R¹ which together with the interjacent groups represent an        optionally substituted heterocyclic group.

Each possibility represents a separate embodiment of the presentinvention.

In various embodiments, the compound having anti-viral activity of thepresent invention is represented by any of the formulae VII, VIII, IX orX as defined herein below:

wherein R¹ and R² together with the interjacent nitrogen atom representa non-aromatic heterocyclic group;

-   -   wherein R¹ represents a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   X represents a carbon atom, a sulfur atom, a sulfoxide group S═O        or a group PR³, P—O—R³ or P—N(R⁴)—R³ where R³ and R⁴ each        independently represent a hydrogen atom or an optionally        substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl        group;    -   Z represents an oxygen atom, a sulfur atom or a group NR⁵ where        R⁵ represents a hydrogen atom or an optionally substituted        alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group; and    -   A represents a hydrogen atom or an optionally substituted alkyl,        alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group, or a group        N(R⁶)₂, NHNH₂, NR⁶NHR⁶ or NR⁶N(R⁶)₂, or a group OR⁶ or SR⁶ where        each R⁶ independently represents a hydrogen atom or an        optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl        or aralkyl group, or a 10α-dihydroartemisinyl group, or A        represents a group OR⁷ or NR⁶R⁷, where R⁶ represents a group as        defined above and R⁷ represents a bond attached as a substituent        to R⁵ together with the interjacent group —X(═Z)— forming an        optionally substituted heterocyclic group where Z represents a        group NR⁵, or R⁷ represents a bond attached as a substituent to        R¹ together with the interjacent group —N—X(═Z)— forming an        optionally substituted heterocyclic group.    -   Each possibility represents a separate embodiment of the present        invention.

Disclosed herein is the use of the compound having anti-viral activityof any of formulae I, VII, VIII, IX or X for the preparation of amedicament for treating a viral infection. The present invention furtherprovides the compound having anti-viral activity of any of formulae I,VII, VIII, IX or X or a pharmaceutical composition comprising same foruse in treating a viral infection.

The term “treating” as used herein includes the diminishment,alleviation, or amelioration of at least one symptom associated orcaused by the state, disorder or disease being treated. In someembodiments, the term “treating” as used herein refers to the inhibitionof viral replication with reduction of viral load. Accordingly, the term“treating” further encompasses prophylaxis or preemptive treatment,namely the prevention of infection and disease in yet uninfected orinfected asymptomatic patients. In one embodiment, the treatment iseffected ex-vivo. The term “a therapeutically effective amount” as usedherein refers to an amount of an agent which is effective, upon singleor multiple dose administration to the subject in providing atherapeutic benefit to the subject. In one embodiment, the therapeuticbenefit is inhibiting virus activity. As used herein, the term“administering” refers to bringing in contact with the compound orcomposition of the present invention. Administration can be accomplishedto cells or tissue cultures, or to living organisms, for examplemammals, in particular humans.

Within the scope of the present invention is a method for suppressingviral replication, the method comprising the step of administering acompound having anti-viral activity of any of formulae I, VII, VIII, IXor X or a composition comprising said compound and a pharmaceuticallyacceptable carrier or excipient. Additional embodiments provide the useof a compound having anti-viral activity of any of formulae I, VII,VIII, IX or X for the preparation of a medicament for suppressing viralreplication. According to some aspects and embodiments, the presentinvention provides a compound having anti-viral activity of any offormulae I, VII, VIII, IX or X or a pharmaceutical compositioncomprising same for use in suppressing viral replication. In aparticular embodiment, the methods and use provided herein are directedto suppressing viral replication in a cell or in an organ culturecomprising the step of contacting the cell or the organ culture with acompound having anti-viral activity of any of formulae I, VII, VIII, IXor X or a composition comprising said compound and a pharmaceuticallyacceptable carrier or excipient.

The alkyl, alkenyl or alkynyl group represented by R¹ in formula I is,in some embodiments, substituted. In another embodiment, the alkyl,alkenyl or alkynyl group is unsubstituted. Each possibility represents aseparate embodiment of the present invention.

The alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl grouprepresented by R¹ or R² in formula I; or represented by R¹, A or Z informula X is, in some embodiments, substituted. In another embodiment,the alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group isunsubstituted. Each possibility represents a separate embodiment of thepresent invention.

As provided herein, 10-amino artemisinin derivatives exhibit extremelyhigh anti-viral efficacy. This property, combined with their excellentsafety and tolerability profiles, renders them an attractive choice fortreatment of viral infections and diseases and disorders engenderedthereby.

In another embodiment, Y of formula I represents a group —NR¹R², whereinR¹ and R² together with the interjacent nitrogen atom form anon-aromatic heterocyclic group. In another embodiment, the non-aromaticheterocyclic group is substituted. In another embodiment, thenon-aromatic heterocyclic group is unsubstituted. Each possibilityrepresents a separate embodiment of the present invention.

In another embodiment, the non-aromatic heterocyclic group issubstituted with a polar moiety.

In another embodiment, the non-aromatic heterocyclic group ispiperazine. In certain embodiments, the non-aromatic heterocyclic groupis morpholine. In another embodiment, the non-aromatic heterocyclicgroup is thiomorpholine. In another embodiment, the non-aromaticheterocyclic group is morpholino-sulfone. In another embodiment, thenon-aromatic heterocyclic group is selected from the group consisting ofpiperazinyl, morpholinyl, thiomorpholinyl, and mopholinosulphonyl. Eachpossibility represents a separate embodiment of the present invention.

In particular embodiments, the compound of the present invention isartemisone (formula VIII). Artemisone, also known as“10α-(4′-(S,S-dioxothiomorpholin-1′-yl)-10-deoxo-10-dihydroartemisin”and “BAY 44-9585,” is available from Bayer AG (Germany).

In another embodiment, the compound of the present invention is10α-(4′-benzylpiperazin-1′-yl)-10-deoxo-10-dihydroartemisinin.

In another embodiment, the compound of the present invention is10α-(morpholino) 10-deoxo-10-dihydroartemisinin.

In another embodiment, the compound of the present invention is10α-(1-(2-pyrimidyl)-piperazino)-10-deoxo-10-dihydroartemisinin.

In another embodiment, the compound of the present invention is10α-(sulfamino)-dihydroartemisinin.

In some embodiments, the compound of the present invention isrepresented by the structure of formula X, wherein R¹ represents ahydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl,cycloalkyl, aryl or aralkyl group; X represents a carbon atom, a sulfuratom, or a sulfoxide group S═O; Z represents an oxygen atom or a sulfuratom; and A represents a N(R⁶)₂, NHNH₂, NR⁶NHR⁶, or NR⁶N(R⁶)₂ group,where each R⁶ independently represents a hydrogen atom or an optionallysubstituted alkyl, alkenyl, alkynyl, cycloalkyl, aryl or aralkyl group.

In particular embodiments, the compound of the present invention isrepresented by the structure of formula I, wherein Y represents a —NR¹R²group, where R¹ represents a hydrogen atom and R² represents an —X(═Z)-Agroup in which, X represents a sulfoxide group S═O, Z represents anoxygen atom, and A represents a NH₂ group.

Any alkyl, alkenyl or alkynyl group, unless otherwise specified, may belinear or branched and may contain up to 12, up to 6, or up to 4 carbonatoms. Non-limiting examples of alkyl groups are methyl, ethyl, propyland butyl. In some embodiments, the alkenyl or alkynyl group is not analk-1-enyl or alk-1-ynyl group. In accordance with these embodiments,there is at least one methylene group —CH₂— or similar sp³-hybridisedcenter between a carbon atom forming part of the double or triple C—Cbond and the nitrogen atom to which the group is attached. Non-limitingexamples of alkenyl and alkynyl groups include propenyl, butenyl,propynyl and butynyl groups. When an alkyl moiety forms part of anothergroup, for example the alkyl moiety of an aralkyl group, it may containup to 6, or up to 4 carbon atoms. Exemplary alkyl moieties are methyland ethyl.

An aryl group may be any aromatic hydrocarbon group and may contain from6 to 24, preferably 6 to 18, more preferably 6 to 16, and especially 6to 14 carbon atoms. Non-limiting examples of aryl groups include phenyl,naphthyl, anthryl, phenanthryl and pyryl groups, especially a phenyl ornapthyl, and particularly a phenyl group. When an aryl moiety forms partof another group, for example the aryl moiety of an aralkyl group, itmay be a phenyl, naphthyl, anthryl, phenanthryl or pyryl, especiallyphenyl or naphthyl, and particularly a phenyl moiety.

An aralkyl group may be any alkyl group substituted by an aryl group.Suitable aralkyl group contains from 7 to 30, particularly 7 to 24 andespecially 7 to 18 carbon atoms. Non-limiting examples of aralkyl groupsinclude benzyl, naphthylmethyl, anthrylmethyl, phenanthrylmethyl andpyrylmethyl groups. An exemplary aralkyl group is a benzyl group.

A cycloalkyl group may be any saturated cyclic hydrocarbon group and maycontain from 3 to 12, for example 3 to 8, and especially 3 to 6 carbonatoms. Non-limiting examples of cycloalkyl groups are cyclopropyl,cyclopentyl and cyclohexyl groups.

A heteroaryl group may be any aromatic monocyclic or polycyclic ringsystem which contains at least one heteroatom. Typically, a heteroarylgroup is a 5-18-membered, particularly a 5-14-membered, and especially a5-10-membered aromatic ring system containing at least one heteroatomselected from an oxygen, a sulfur and a nitrogen atom. Non-limitingheteroaryl groups include pyridyl, pyrylium, thiopyrylium, pyrrolyl,furyl, thienyl, indolinyl, isoindolinyl, indolizinyl, imidazolyl,pyridonyl, pyronyl, pyrimidinyl, pyrazinyl, oxazolyl, thiazolyl,purinyl, quinolinyl, isoquinolinyl, quinoxalinyl, pyridazinyl,benzofuranyl, benzoxazolyl and acridinyl groups. A C-linked heteroarylgroup is a heteroaryl group as defined above which is linked to thetetracyclic 1,2,4-trioxane moiety of a compound of the present inventionvia a carbon atom in the heteroaromatic ring system.

A heterocyclic group may be any monocyclic or polycyclic ring systemwhich contains at least one heteroatom and may be unsaturated orpartially or fully saturated. The term “heterocyclic” thus includesheteroaryl groups as defined above as well as non-aromatic heterocyclicgroups. Typically, a heterocyclic group is a 3-18-membered, particularlya 3-14-membered, especially a 5-10-membered ring system containing atleast one heteroatom selected from an oxygen, a sulfur and a nitrogenatom. Non-limiting examples of heterocyclic groups include the specificheteroaryl groups named above as well as pyranyl, piperidinyl,pyrrolidinyl, dioxanyl, piperazinyl, morpholinyl, thiomorpholinyl,morpholinosulphonyl, tetrahydroisoquinolinyl and tetrahydrofuranylgroups.

A heterocyclylalkyl group may be any alkyl group substituted by aheterocyclic group. Typically, the heterocyclic moiety is a3-18-membered, particularly a 3-14-membered, and especially a5-10-membered heterocyclic group as defined above and the alkyl moietyis a C₁₋₆ alkyl, or C₁₋₄ alkyl, for example a methyl group.

An amino acid may be any α-amino acid, such as glycine, alanine, valine,leucine, isoleucine, serine, threonine, cysteine, cystine, methionine,aspartic acid, glutamic acid, aspargine, glutamine, lysine,hydroxylysine, arginine, histidine, phenylalanine, tyrosine, tryptophan,proline, hydroxyproline or phenylglycine, and includes both D- andL-configurations. An amino acid ester may be any ester of such an aminoacid, for example alkyl esters such as C₁₋₄ alkyl esters.

When any of the foregoing substituents are designated as beingoptionally substituted, the substituent groups which are optionallypresent may be any one or more of those customarily employed in thedevelopment of pharmaceutical compounds and/or the modification of suchcompounds to influence their structure/activity, stability,bioavailability or other property. Specific examples of suchsubstituents include, for example, halogen atoms, nitro, cyano,hydroxyl, cycloalkyl, alkyl, alkenyl, haloalkyl, alkoxy, haloalkoxy,amino, alkylamino, dialkylamino, formyl, alkoxycarbonyl, carboxyl,alkanoyl, alkylthio, alkylsulphinyl, alkylsulphonyl, alkylsulphonato,arylsulphinyl, arylsulphonyl, arylsulphonato, carbamoyl, alkylamido,aryl, aralkyl, optionally substituted aryl, heterocyclic and alkyl- oraryl-substituted heterocyclic groups. When any of the foregoingsubstituents represents or contains an alkyl or alkenyl substituentgroup, this may be linear or branched and may contain up to 12, up to 6,and especially up to 4 carbon atoms. A cycloalkyl group may contain from3 to 8, for example from 3 to 6 carbon atoms. An aryl group or moietymay contain from 6 to 10 carbon atoms, for example phenyl groups. Aheterocyclic group or moiety may be a 5-10-membered ring system asdefined above. A halogen atom may be a fluorine, chlorine, bromine oriodine atom and any group which contains a halo moiety, such as ahaloalkyl group containing any one or more of these halogen atoms.

In one aspect, Y may represent a halogen atom, particularly a fluorineor bromine, and especially a fluorine atom.

In another aspect, Y may represent a C₃₋₈ cycloalkyl group, a C₆₋₁₈ arylgroup, a 5-10-membered C-linked heteroaryl group or a 5-10-memberedheterocyclyl-C₁₋₆ alkyl group, each group being optionally substitutedby one or more substituents selected from the group consisting ofhalogen atoms, hydroxyl, C₁₋₄ alkyl, C₂₋₄ alkenyl, C₁₋₄ haloalkyl, C₁₋₄alkoxy, amino, C₁₋₄ alkylamino, di(C₁₋₄ alkyl)amino, carboxyl, C₆₋₁₀aryl, 5-10-membered heterocyclic and C₁₋₄ alkyl- or phenyl-substituted5-10-membered heterocyclic groups. Each possibility represents aseparate embodiment of the present invention. According to some aspectsand embodiments, Y may represent a C₆₋₁₈ aryl group optionallysubstituted by one or more substituents selected from the groupconsisting of halogen atoms, hydroxyl, C₁₋₄ alkyl, C₂₋₄ alkenyl, C₁₋₄haloalkyl, C₁₋₄ alkoxy, C₁₋₄ haloalkoxy, amino, C₁₋₄ alkylamino, di(C₁₋₄alkyl)amino and carboxyl groups. Each possibility represents a separateembodiment of the present invention. In particular, Y may represent aphenyl, naphthyl, anthryl or phenanthryl group, each group beingoptionally substituted by one or more substituents selected from thegroup consisting of halogen atoms and hydroxyl, methyl, vinyl, C₁₋₄alkoxy and carboxyl groups. Each possibility represents a separateembodiment of the present invention.

In another sub-group of compounds, Y may represent a phenyl,fluorophenyl, chlorophenyl, bromophenyl, triethylphenyl, vinylphenyl,methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, carboxylphenyl,naphthyl, hydroxynaphthyl, methoxynaphthyl, anthryl or phenanthrylgroup. Each possibility represents a separate embodiment of the presentinvention. Compounds in which Y may represent a phenyl ortrimethoxyphenyl group are also included within the scope of the presentinvention.

In a further aspect, Y may represent a group —NR¹R² where R¹ representsa hydrogen atom or a C₁₋₆ alkyl group and R² represents a C₁₋₆ alkyl,C₃₋₄ cycloalkyl, C₆₋₁₀ aryl or C₇₋₁₆ aralkyl group, or R¹ and R²together with the interjacent nitrogen atom represent a 5-10-memberedheterocyclic group or an amino group derived from a C₁₋₆ alkyl ester ofan amino acid, each group being optionally substituted by one or moresubstituents selected from the group consisting of halogen atoms, C₁₋₄alkyl, C₁₋₄ haloalkyl, C₁₋₆ alkoxycarbonyl, phenyl, halophenyl, C₃₋₄alkylphenyl, C₁₋₄ haloalkylphenyl, C₁₋₄ alkoxyphenyl, benzyl, pyridyland pyrimidinyl groups. Each possibility represents a separateembodiment of the present invention. In particular, Y may represent agroup —NR¹R² where R¹ represents a hydrogen atom or a C₁₋₄ alkyl groupand R² represents a C₁₋₄ alkyl, C₃₋₆ cycloalkyl, phenyl or benzyl group,or R¹ and R² together with the interjacent nitrogen atom represent a6-10-membered heterocyclic group or an amino group derived from a C₁₋₄alkyl ester of an amino acid, each group being optionally substituted byone or more substituents selected from the group consisting of halogenatoms, C₁₋₄ haloalkyl, C₁₋₄ alkoxycarbonyl, phenyl, halophenyl, C₁₋₄alkylphenyl, C₁₋₄ haloalkylphenyl, C₁₋₄ alkoxyphenyl, benzyl, pyridyland pyrimidinyl groups. Each possibility represents a separateembodiment of the present invention.

In another sub-group of these compounds, Y represents a propylamino,cyclopentylamino, cyclohexylamino, phenylamino, fluorophenylamino,chlorophenylamino, bromophenylamino, iodophenylamino,methoxycarbonylphenylamino, biphenylamino, benzylamino,fluorobenzylamino, bis(trifluoromethyl)-benzylamino, phenylethylamine,phenylmethoxycarbonyl methylamino, diethylamino, morpholinyl,thiomorpholinyl, morpholinosulphonyl, indolinyl,tetrahydroisoquinolinyl, phenylpiprerazinyl, fluorophenylpiperazinyl,chlorophenylpiperazinyl, methylphenylpiperazinyl,trifluoromethylphenylpiperazinyl, methoxyphenylpiperazinyl,benzylpiperazinyl, pyridylpiperazinyl and pyrimidinylpiperazinyl group.Exemplary compounds include, but are not limited to, compounds in whichY represents a propylamino, phenylamino, bromophenylamino,iodophenylamino, biphenylamino, benzylamino,bis(trifluoromethyl)benzylamino, phenylethylamino,phenyl-methoxycarbonylmethyl amino or morpholinyl group. Eachpossibility represents a separate embodiment of the present invention.

In another embodiment, a method of the present invention utilizes acompound of the general formula I as defined above, with the provisothat, when Y is a group —NR¹R² and R² represents a phenyl,3-chlorophenyl, 4-chlorophenyl, 3-bromophenyl, 4-bromophenyl,4-iodophenyl, 4-methylphenyl, 4-methoxyphenyl, 3-carboxylphenyl or4-carboxylphenyl group, then R¹ is an optionally substituted alkylgroup.

One or more of the compounds of the invention, may be present as a salt.Suitable salts of artemisinin derivatives of the present inventioninclude both basic and acid addition salts. In particular embodiments,acid addition salts, which can be formed by the reaction of a suitablecompound of formulae I, VII, VIII, IX or X with a suitable acid, such asan organic acid or a mineral acid are encompassed by the presentinvention. Acid addition salts formed by the reaction with a mineralacid are suitable according to the principles of the present invention,especially salts formed by reaction with hydrochloric or hydrobromicacid. Compounds of formula I in which Y represents a group —NR¹R²,wherein R¹ and R² are as defined above, are particularly suitable forthe formation of such acid addition salts.

It should also be appreciated that the compounds of general formulae I,VII, VIII, IX or X are capable of existing as different geometric andoptical isomers. The present invention thus includes both the individualisomers and mixtures of such isomers. The present invention alsoincludes solvates of the compounds of the present invention and solvatesof salts as described herein. “Solvate” means a physical association ofa compound of the invention with one or more solvent molecules. Thisphysical association involves varying degrees of ionic and covalentbonding, including hydrogen bonding. “Solvate” encompasses bothsolution-phase and isolatable solvates. Non-limiting examples ofsuitable solvates include ethanolates, methanolates and the like.“Hydrate” is a solvate wherein the solvent molecule is water.

The present invention also includes polymorphs of the compounds of thepresent invention and salts thereof. The term “polymorph” refers to aparticular crystalline or amorphous state of a substance, which can becharacterized by particular physical properties such as X-raydiffraction, IR or Raman spectra, melting point, and the like.

Methods for producing the compounds of the present invention are knownin the art, and are described inter alia in U.S. Pat. No. 6,984,640 andUnited States patent application 2005/0119232, the contents of which areincorporated herein by reference.

In another embodiment, the compounds of the present invention exhibitsan aqueous solubility at pH 7.2 greater than 40 mg/L. In otherembodiments, the aqueous solubility is within the range of about 40-1000mg/L. In yet other embodiments, the aqueous solubility is within therange of about 30-1000 mg/L. In further embodiments, the aqueoussolubility is within the range of about 50-1000 mg/L. In additionalembodiments, the aqueous solubility is within the range of about 60-1000mg/L. In various embodiments, the aqueous solubility is within the rangeof about 40-800 mg/L. In certain embodiments, the aqueous solubility iswithin the range of about 40-600 mg/L. In some embodiments, the aqueoussolubility is within the range of about 40-400 mg/L. In otherembodiments, the aqueous solubility is within the range of about 40-2000mg/L. In particular embodiments, the aqueous solubility is within therange of about 20-1000 mg/L. In yet another embodiment, the aqueoussolubility is within the range of about 20-800 mg/L. Each possibilityrepresents a separate embodiment of the present invention.

According to some aspects and embodiments, the compounds of the presentinvention exhibit a log P between about 2.0-3.0, inclusive. log P, asused herein, refers to the octanol-water partition coefficient. Incertain embodiments, the log P is between about 2.1-2.9, inclusive. Inanother embodiment, the log P is between about 2.2-2.8, inclusive. Inyet another embodiment, the log P is between about 2.3-2.7, inclusive.In additional embodiments, the log P is between about 2.1-3.0,inclusive. In further embodiments, the log P is between about 2.2-3.0,inclusive. In other embodiments, the log P is between about 2.0-2.9,inclusive. In certain embodiments, the log P is between about 2.0-2.8,inclusive. In particular embodiments, the log P is between about2.4-2.8, inclusive. Each possibility represents a separate embodiment ofthe present invention.

According to some aspects and embodiments, the compounds of the presentinvention are not capable of being substantially converted in vivo todihydroartemisinin. It is contemplated that this property enhances thesafety of these compounds by reducing the already low likelihood ofneurotoxicity. “Substantially converted” as used herein refers to invivo conversion to dihydroartemisinin to an extent detectable bystandard metabolic fate assays. Metabolic fate assays are well known inthe art, and include, for example, administration of a compound of thepresent invention labeled with ¹⁴C or ²H to human liver microsomes,followed by identification of metabolites produced by 1D and 2D nuclearmagnetic resonance (NMR) (Haynes et al., Angew. Chem. Int. Ed., 2006,45, 2082-2088). In another embodiment, any other metabolic fate assayknown in the art is utilized. Each possibility represents a separateembodiment of the present invention.

In certain embodiments, the viral infection which is treated, inhibited,attenuated or suppressed by a method of the present invention is aherpesvirus infection. In another embodiment, the herpesvirus isselected from the group consisting of herpes simplex virus (HSV) type 1,HSV type 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus(EBV), human herpesvirus 6, human herpesvirus 7, and human herpesvirus 8(Kaposi's Sarcoma associated Herpes Virus). Each possibility representsa separate embodiment of the present invention. Human herpesvirus 6 asused herein encompasses both variants A and B. Each possibilityrepresents a separate embodiment of the present invention. In anotherembodiment, the viral infection is an alpha herpesvirus infection. Incertain embodiments, the viral infection is a beta herpesvirusinfection. In another embodiment, the viral infection is a gammaherpesvirus infection. In yet another embodiment, the viral infection isa cytomegalovirus infection. In an exemplary embodiment, the viralinfection is a human cytomegalovirus infection. In another embodiment,the viral infection is a flavivirus infection. In specific embodiments,the flavivirus infection is Bovine Viral Diarrhea virus (BVDV)infection. In other embodiments, the viral infection is hepatitis Bvirus (HBV) infection or hepatitis C virus (HCV) infection. Eachpossibility represents a separate embodiment of the present invention.In further embodiments, the viral infection is any other type of viralinfection known in the art.

It will be understood by those skilled in the art that the compositionsand methods of the present invention have utility for treating not onlyviral infections themselves, but also diseases and disorders engenderedby viral infections. Thus, for example, the present invention provides amethod of treating a viral infection having oncomodulatory activity on atumor in a subject in need thereof comprising administering to saidsubject a therapeutically effective amount of a compound havinganti-viral activity of any of formulae I, VII, VIII, IX or X as definedherein or a pharmaceutical composition comprising said compound and apharmaceutically acceptable carrier or excipient. For example, there issome evidence that HCMV could modulate the malignant phenotype inglioblastomas, where HCMV sequences and viral gene expression exist inmost, if not all, malignant gliomas (Dziurzynski et al., 2012,Neuro-Oncology, doi:10.1093/neuonc/nor227). Thus, according to someaspects and embodiments, the present invention provides a method oftreating a viral infection having oncomodulatory activity on a tumor, inparticular glioblastoma associated with cytomegalovirus in a subject inneed thereof, the method comprising administering to said subject atherapeutically effective amount of a compound having anti-viralactivity of any of formulae I, VII, VIII, IX or X as defined herein or apharmaceutical composition comprising said compound and apharmaceutically acceptable carrier or excipient. The method of thepresent invention encompasses the direct targeting of cytomegalovirus inglioblastoma patients or alternatively modulating the transformedphenotype in glioblastoma patients. Each possibility represents aseparate embodiment of the present invention. In some embodiments, thecompounds of the present invention prevent or decrease the likelihood ofdeveloping glioblastoma in subjects who are afflicted withcytomegalovirus.

Further encompassed by the present invention is the treatment of CMVinfection, wherein the CMV is associated with a tumor such as, but notlimited to, colon cancer, prostate cancer and the like, and thetreatment of EBV, wherein the EBV is associated with a tumor such as,but not limited to, Burkitt's lymphoma, Hodgkin's lymphoma, posttransplantation lympho-proliferative disorder (PTLD), and nasopharyngealcarcinoma. Each possibility represents a separate embodiment of thepresent invention.

It will also be understood by those skilled in the art that thecompounds of the present invention are useful for prevention,attenuation or treatment and control of viral infection and disease inhumans and animals. In some embodiments, the treatment is effective incases of congenital infection. In additional embodiments, the treatmentis effective in cases of CMV infection in immunosuppressed patientsincluding transplantation recipients. In particular embodiments thetreatment is effective ex-vivo. Within the scope of the presentinvention is the treatment of newborns that are infected with HCMV,pregnant women who are infected with HCMV, and transplantationrecipients. Each possibility represents a separate embodiment of thepresent invention.

According to certain aspects and embodiments, the present inventionprovides the combination therapy comprising the compounds of the presentinvention and at least one other antiviral drug. In one embodiment, thecompound of the present invention is used in combination with a viralDNA polymerase inhibitor. In another embodiment, the viral DNApolymerase inhibitor is selected from the group consisting ofganciclovir, foscarnet and cidofovir. Each possibility represents aseparate embodiment of the present invention. In yet another embodiment,the viral DNA polymerase inhibitor is any other viral DNA polymeraseinhibitor known to those of skill in the art. In certain embodiments, acompound of the present invention is used in combination with ananti-viral drug including, but not limited to ganciclovir,valganciclovir, foscarnet, cidofovir, acyclovir, valacyclovir, and anyother anti-viral drug known in the art. Each possibility represents aseparate embodiment of the present invention. In additional embodiments,a compound of the present invention is used in combination with any oneof maribavir, letermovir (also known as AIC246), CMX-001, CMVhyperimmune globulins and CMV monoclonal antibodies. Each possibilityrepresents a separate embodiment of the present invention.

Should the compositions of the present invention be administered as acombination therapy with additional therapeutic agents (e.g. otheranti-viral agents), the treatment may take place sequentially in anyorder, simultaneously or a combination thereof. For example,administration of a compound of the invention can take place prior to,after or at the same time as administration of the additionaltherapeutic agent(s). For example, a total treatment period can bedecided for the compound of the invention. The additional agent(s) canbe administered prior to the onset of treatment with the compound of theinvention or following treatment with the compound of the invention. Inaddition, the additional agent(s) can be administered during the periodof administering the compound of the invention but does not need tooccur over the entire treatment period. In another embodiment, thetreatment regimen includes pre-treatment with one agent, followed by theaddition of the other agent or agents. Alternating sequences ofadministration are also contemplated. Alternating administrationincludes administration of a compound of the invention, followed by theadditional agent, followed by a compound of the invention, etc. Thetherapeutic efficacy of the combination of a compound of the inventionand the additional agent(s) is at least additive. In some embodiments,the therapeutic efficacy is synergistic, namely the overall dose of eachof the components may be lower, thus resulting in significantly lowerside effects experienced by the subject, while a sufficient antiviraleffect is nonetheless achieved.

In another embodiment, the pharmaceutical composition that comprises acompound having anti-viral activity of any of formulae I, VII, VIII, IXor X as defined herein as active ingredient, may further comprise apharmaceutically acceptable carrier or excipient.

A pharmaceutically acceptable carrier or excipient may be any materialwith which the active ingredient is formulated to facilitateadministration. A carrier or excipient may be a solid or a liquid,including a material which is normally gaseous but which has beencompressed to form a liquid, and any of the carriers or excipientsnormally used in formulating pharmaceutical compositions. Typically,compositions according to the invention contain 0.5 to 95% by weight ofactive ingredient.

The compounds of the present invention can be formulated as, forexample, tablets, pills, capsules, pellets, granules, powders, lozenges,sachets, cachets, elixirs, suspensions, dispersions, emulsions,solutions, syrups, aerosols, ointments, soft and hard gelatin capsules,suppositories, sterile injectable solutions, and sterile packagedpowders. Each possibility represents a separate embodiment of thepresent invention. These formulations can be produced by known methodsusing conventional solid carriers or excipients such as, for example,lactose, starch or talcum or liquid carriers such as, for example,water, fatty oils or liquid paraffins. Other carriers or excipientswhich may be used include, but are not limited to, materials derivedfrom animal or vegetable proteins, such as the gelatins, dextrins andsoy, wheat and psyllium seed proteins; gums such as acacia, guar, agar,and xanthan; polysaccharides; alginates; carboxymethylcelluloses;carrageenans; dextrans; pectins; synthetic polymers such aspolyvinylpyrrolidone; polypeptide/protein or polysaccharide complexessuch as gelatin-acacia complexes; sugars such as mannitol, dextrose,galactose and trehalose; cyclic sugars such as cyclodextrin; inorganicsalts such as sodium phosphate, sodium chloride and aluminium silicates;and amino acids having from 2 to 12 carbon atoms and derivatives thereofsuch as, but not limited to, glycine, L-alanine, L-aspartic acid,L-glutamic acid, L-hydroxyproline, L-isoleucine, L-leucine andL-phenylalanine. Each possibility represents a separate embodiment ofthe present invention.

Auxiliary components such as tablet disintegrants, solubilisers,preservatives, antioxidants, surfactants, viscosity enhancers, coloringagents, flavoring agents, pH modifiers, sweeteners or taste-maskingagents may also be incorporated into the composition. Suitable coloringagents include, but are not limited to, red, black and yellow ironoxides and FD & C dyes such as FD & C blue No. 2 and FD & C red No. 40available from Ellis & Everard. Suitable flavoring agents include, butare not limited to, mint, raspberry, liquorice, orange, lemon,grapefruit, caramel, vanilla, cherry and grape flavors and anycombinations thereof. Suitable pH modifiers include, but are not limitedto, citric acid, tartaric acid, phosphoric acid, hydrochloric acid andmaleic acid. Suitable sweeteners include, but are not limited to,aspartame, acesulfame K and thaumatin. Suitable taste-masking agentsinclude, but are not limited to, sodium bicarbonate, ion-exchangeresins; cyclodextrin inclusion compounds, adsorbates ormicroencapsulated actives. Each possibility represents a separateembodiment of the present invention.

In certain embodiments, a delivery vehicle is used. An exemplarydelivery vehicle for the pharmaceutical compositions of the presentinvention is a liposome. A liposome is capable of remaining stable in asubject for a sufficient amount of time to deliver a compound of thepresent invention to the subject. A liposome within the scope of thepresent invention is preferably stable in the subject into whom it hasbeen administered for at least about 30 minutes, more preferably for atleast about 1 hour and even more preferably for at least about 24 hours.

Suitable routes of administration of the compounds and compositions ofthe present invention include, for example, oral, rectal, transdermal,topical, transmucosal, especially transnasal, intestinal or parenteraldelivery, including intramuscular, subcutaneous and intramedullaryinjections as well as intrathecal, direct intraventricular, intravenous,inrtaperitoneal, intranasal, intraarterial, intravesicle (into thebladder) or intraocular injections. Each possibility represents aseparate embodiment of the present invention.

According to certain aspects and embodiments, the compounds andcompositions of the present invention are particularly suitable for oraladministration. It is contemplated that by orally administering thecompounds and compositions of the present invention, a systemic effectcan be achieved. In one embodiment, the compounds and compositions ofthe present invention are administered through nasal respiratory route.Compositions in pharmaceutically acceptable solvents may be nebulized byuse of inert gases. Nebulized solutions may be breathed directly fromthe nebulizing device or the nebulizing device may be attached to a facemasks tent, or intermittent positive pressure breathing machine.Solution, suspension, or powder compositions may be administered, orallyor nasally, from devices that deliver the composition in an appropriatemanner.

Solutions or suspensions used for parenteral, intradermal, orsubcutaneous application typically include the following components: asterile diluent such as water for injection, saline solution, fixedoils, polyethylene glycols, glycerine, propylene glycol (or othersynthetic solvents), antibacterial agents (e.g., benzyl alcohol, methylparabens), antioxidants (e.g., ascorbic acid, sodium bisulfite),chelating agents (e.g., ethylenediaminetetraacetic acid), buffers (e.g.,acetates, citrates, phosphates), and agents that adjust tonicity (e.g.,sodium chloride, dextrose). The pH can be adjusted with acids or bases,such as hydrochloric acid or sodium hydroxide, for example. Theparenteral preparation can be enclosed in ampules, disposable syringesor multiple dose glass or plastic vials.

Pharmaceutical compositions adapted for parenteral administrationinclude, but are not limited to, aqueous and non-aqueous sterileinjectable solutions or suspensions, which can contain antioxidants,buffers, bacteriostats and solutes that render the compositionssubstantially isotonic with the blood of an intended recipient. Suchcompositions can also comprise water, alcohols, polyols, glycerine andvegetable oils, for example. Extemporaneous injection solutions andsuspensions can be prepared from sterile powders, granules and tablets.Such compositions preferably comprise a therapeutically effective amountof a compound of the invention and/or other therapeutic agent(s),together with a suitable amount of carrier so as to provide the form forproper administration to the subject.

The administration regimen can be determined by a skilled artisandepending on the infection and the severity of the condition, thepatient population, age, weight etc. The amount of a compound of theinvention that will be effective in the treatment of a particulardisorder or condition, including HCMV, will depend on the nature of thedisorder or condition, and can be determined by standard clinicaltechniques. In addition, in vitro assays, animal assays (e.g. the guineapig trans-placental transmission model and the newborn mouse model) andthe ex-vivo assay described herein below, may optionally be employed tohelp identify optimal dosage ranges. The precise dose to be employedalso depends on the route of administration, and the progression of thedisease or disorder, and should be decided according to the judgment ofthe practitioner and each patient's circumstances. Typically dosage inthe range of 0.01-1000 mg/kg of body weight, 0.1 mg/kg to 100 mg/kg, 1mg/kg to 100 mg/kg, 10 mg/kg to 75 mg/kg, etc. may be used. Exemplary,non-limiting amounts of the compounds of the present invention include0.1 mg/kg, 0.2 mg/kg, 0.5 mg/kg, 1 mg/kg, 5 mg/kg, 10 mg/kg, 20 mg/kg,50 mg/kg, 60 mg/kg, 75 mg/kg and 100 mg/kg. Each possibility representsa separate embodiment of the present invention. Alternatively, theamount administered can be measured and expressed as molarity of theadministered compound. By way of illustration and not limitation, acompound of the present invention (e.g. a compound of any of formulae I,VII, VIII, IX, or X) can be administered in a range of 0.1 μM to 10 mM,e.g., about 0.1 μM, 10 μM, 100 μM, 1 mM, and 10 mM. Alternatively, theamount administered can be measured and expressed as mg/ml, μg/ml, orng/ml. By way of illustration and not limitation, an anti-viral agentcan be administered in an amount of 1 ng/ml to 1000 mg/ml, for example1-1000 ng/ml, 1-100 ng/ml, 1-1000 μg/ml, 1-100 μg/ml, 1-1000 mg/ml,1-100 mg/ml etc. Effective doses may be extrapolated from dose-responsecurves derived from in vitro, animal model or ex-vivo model testbioassays or systems.

The administration schedule can be taken once-daily, twice-daily,thrice-daily, once-weekly, twice-weekly, thrice-weekly, once-monthly,twice-monthly, thrice-monthly, or any other administration scheduleknown to those of skill in the art. In addition, the administration canbe continuous, i.e., every day, or intermittently. The terms“intermittent” or “intermittently” as used herein means stopping andstarting at either regular or irregular intervals. For example,intermittent administration can be administration in one to six days perweek or it may mean administration in cycles (e.g. daily administrationfor two to eight consecutive weeks, then a rest period with noadministration for up to one week) or it may mean administration onalternate days.

The following examples are presented in order to more fully illustratesome embodiments of the invention. They should, in no way be construed,however, as limiting the broad scope of the invention.

EXPERIMENTAL DETAILS SECTION Example 1 Highly Potent Anti-Viral Activityof Artemisone and Compound IX as Determined by Plaque Reduction AssayMaterials and Experimental Methods Virus, Cells, and Tested Compounds

The CMV strains used were: AD169 (obtained from the American TypeCulture Collection), and TB40/E. In addition, low-passage clinicalisolates CI704, and CI893, recovered at the Hadassah Clinical VirologyLaboratory from the urine of congenitally-infected newborns, andpropagated for 3-5 passages, were used for some experiments. All CMVstrains were propagated and titered in human foreskin fibroblasts (HFF)cells. Cell-free virus stocks and cell-associated clinical isolates weremaintained at −70° C. Viral stocks were titered by serial 10-folddilution in 24-well tissue culture plates containing HFF monolayersoverlaid with agarose-medium. After incubation for 7 to 10 days, plaqueswere enumerated, and virus titer was determined as plaque forming units(PFU) per milliliter (ml). Stocks of artemisone, artemiside, RW177,compound IX, and artesunate were freshly prepared at 10 mM concentrationin DMSO. Ganciclovir, stored as 10 mM stock was used in comparativeassays.

Plaque Reduction Assay

Cell monolayers were inoculated in 24-well culture plates with 0.2 ml ofvirus suspension containing 60 to 100 PFU per well. After adsorption for60 min at 37° C., the inoculum was removed, and culture medium wasreplaced with agarose-medium overlay containing the tested drug. Thefollowing final drug concentrations were used: Artemisone: 0, 0.1, 1, 5,10, 25, and 50 μM; Artesunate: 0, 1, 5, 10, 25, 50, and 100 μM;Ganciclovir, artemiside, compound IX and RW177: 0, 0.1, 1, 5, 10, 25,and 50 μM. Plates were incubated for 10 days at 37° C. in a 5% CO₂incubator. Plaques were then counted microscopically. The drugconcentration required to reduce the number of plaques to 50% of thecontrol value (IC₅₀), was calculated.

Results

Antiviral activity of artemisone was determined by applying various drugconcentrations to a growing virus in cell culture, using a standardplaque reduction assay. Artesunate, a compound known to have significantanti-viral activity, was tested in parallel. Ganciclovir was used as anadditional positive control. The IC₅₀ values of at least three separateexperiments with each drug and virus were averaged, and the results arereported as mean±standard deviation values. Representative curves ofplaque reduction assay for artemisone and artesunate are depicted inFIGS. 2A and 3A, respectively. Artemisone exhibited similar antiviralactivity (0.9±0.3 μM) to that of ganciclovir, while demonstrating nocytotoxicity. By comparison, the mean IC₅₀ value of artesunate was10.8±4.2 μM. Thus, artemisone possesses enhanced antiviral efficacy farsuperior to that of artesunate Importantly, artemisone demonstratedbroad CMV antiviral activity against both laboratory-derived CMV strainsand low-passage CMV clinical isolates. Superior antiviral activity ofartemisone compared to artesunate was also demonstrated in an additionalcell-type culture system of retinal epithelial cells (RPE). The CMVantiviral activity of compound IX was also found to be superior withIC₅₀ values of 2.1±0.6 μM. Hence, compound IX of the present inventioncan also be used as an effective anti-CMV agent.

In contrast, the 10-alkylamino artemisinin derivatives artemiside andRW177 (FIG. 1), which possess enhanced activity against parasites, hadsignificantly inferior antiviral activity (IC₅₀ values >40 μM),emphasizing the enhanced and surprising antiviral activity of artemisoneand compound IX.

Example 2 Confirmation of Highly Potent Anti-Viral Activity ofArtemisone by Viral DNA Quantitation Materials and Experimental Methods

Quantification of Viral DNA

Viral DNA quantity in infected cells with and without added drugs(expressed as genome copies/well) was determined by real-time PCR assay,following DNA extraction from cells, with the use of primers and probederived from the CMV gB gene. The assay is known to demonstrate a linearquantitation over a 6-log range with a sensitivity of 50 copies/ml.

Results

The results of Example 1 were confirmed by quantitation of viral DNAusing real-time PCR. These assays confirmed that artemisone possessesenhanced antiviral efficacy, far superior to that of artesunate.Representative curves of viral DNA accumulation for artemisone andartesunate are depicted in FIGS. 2B and 3B, respectively.

Thus, antiviral susceptibility and viral DNA quantitation assaysrevealed that artemisone is a highly effective inhibitor of CMVreplication and viral DNA synthesis.

Example 3 Artemisone Effectively Inhibits CMV Immediate Early (IE) GeneExpression Materials and Experimental Methods Analysis of Viral GeneExpression

Human foreskin fibroblasts (HFF) were infected with HCMV strain AD169.At 1 hour post infection (hpi), artemisone (25 μM) or ganciclovir (25μM) were added to the growth medium, and the cells were furtherincubated in the presence of the drug, until prepared forimmunofluorescence analysis at 24 and 72 hpi—to analyze the expressionof IE and pp65, respectively. Control untreated infected cells, andmock-infected cells were analyzed in parallel.

Immunofluorescence Assay

Cells grown on 8-well glass slides were infected at a multiplicity ofinfection (moi) of 0.1 PFU/cell. Supernatant was removed at 24 and 72hpi, and cells were washed 3 times with PBS and fixed with 3.7%formaldehyde for 30 minutes at room temperature. Cells were washed 5times with PBS+1% NH₄Cl, permeabilized by 0.1% TX100 for 5 minutes andwashed 5 times with PBS+1% NH₄Cl. After 1 hour of blocking using 1% BSAin PBS, the indicated primary monoclonal antibodies (IE1/2 or pp65) wereadded to the cells in appropriate dilution in 0.5% BSA in PBS andincubated either at room temperature for 2 hours or overnight at 4° C.The secondary antibody was added to the cells in appropriate dilution inPBS containing 0.5% BSA for 30 minutes at room temperature and washed byPBS.

Following mounting with commercial mounting media, with addition of4′,6-diamidino-2-phenylindole (DAPI) nuclear stain (yielding nuclearblue stain in all cells), the cells were analyzed by fluorescencemicroscopy. Results were monitored on at least 3 independentexperiments, scoring at least 5 fields (of between 500 and 800 cellseach) for each treatment arm.

Results

Representative immune-fluorescence images obtained in artemisone andganciclovir-treated infected cells are depicted in FIG. 4. Artemisonetreatment resulted in a significant reduction of viral IE geneexpression at 24 hpi. This is in sharp contrast to the results obtainedwhen treating with ganciclovir, which did not inhibit IE gene expression(Table 1; FIG. 5A).

Consistent with the reduction in IE gene expression, artemisonetreatment, as ganciclovir, resulted in a highly efficient reduction ofviral late (pp65) gene expression (Table 1; FIGS. 4, 5B).

TABLE 1 Cell count results of total and HCMV antigen-positive cells.Drug treatment/ Total cells CMV antigen- CMV antigen- analyzed CMVcounted per field positive cells per positive cells antigen (N)* field(N)* (%) Control untreated/ 664 ± 23  45 ± 20 6.78 IE1 ± IE2 Artemisone/765 ± 31 0 0 IE1 ± IE2 Ganciclovir/ 553 ± 42 33 ± 5 5.97 IE1 ± IE2Control untreated/ 647 ± 67 115 ± 23 17.77 pp65 Artemisone/ 798 ± 43 0 0pp65 Ganciclovir/ 555 ± 22    1 ± 0.25 0.18 pp65 *At least 5 fields werecounted in each experiment.

Whereas ganciclovir does not inhibit HCMV immediate early (IE) geneexpression, artemisone effectively inhibits IE gene expression and bothartemisone and ganciclovir effectively inhibit HCMV late geneexpression. Thus, without being bound by any theory or mechanism ofaction it is contemplated that artemisone demonstrates a novel mechanismof action, different from that of ganciclovir, which involves inhibitionof a very early step of viral replication preceding viral DNA synthesis.

Example 4 Combination Therapy with Artemisone

To investigate the effect of the artemisone treatment on the efficacy ofconventional anti-HCMV drugs, HCMV-infected cells were treated with acombination of artemisone and ganciclovir. Using intermediateconcentrations of ganciclovir (1 μM), the combined treatment withartemisone led to additive inhibitory effects on HCMV replication.

Example 5 Evaluating Therapeutic Efficiency

In order to evaluate the therapeutic efficacy of the anti-CMV compoundsof the present invention, an ex-vivo model of HCMV infection in maternaldecidua is used as described in J. Virol., 2011; 85: 13204-13213, thecontent of which is hereby incorporated in its entirety. In particular,the study of HCMV transmission and pathogenesis is largely limited bythe absence of animal models for HCMV infection. While the guinea pigtrans-placental transmission model and the newborn mouse model haveproven invaluable for the experimental evaluation of vaccines andvirus-induced brain-pathology, the species specificity of HCMV hasprecluded experimental modeling of congenital human infection. Theex-vivo infected decidual cultures can serve as a unique surrogate humanmodel for screening therapeutic treatments. Using the ex-vivo model, thevarious physiological and pathological processes occurring in responseto treatment with the artemisinin derivatives of the present invention,can be monitored thereby enabling the determination of the efficacy oftreatment.

Materials and Experimental Methods Cells and Viruses

Primary human foreskin fibroblasts (HFF) were used to propagate andisolate HCMV strains as described in Wolf et al., PNAS, 2001, 98,1895-900; and Wolf et al., J. Clin. Invest., 1995, 95, 257-63, thecontent of each of which is hereby incorporated in its entirety. HFFwere grown in Dulbecco's Modified Eagle's Medium (DMEM) supplementedwith 10% fetal bovine serum, 2 mM glutamine, 100 IU/ml penicillin, 100μg/ml streptomycin (Biological industries, Beit Haemek, Israel) and 0.25μg/ml fungizone (Invitrogen, CA, USA). The HCMV strains used were AD169(obtained from the American Type Culture Collection), TB40/E strainexpressing UL32-fused GFP (provided by C. Sinzger, Germany), TB40/Estrain expressing UL83-fused GFP (strain RV1305; provided by M. Winkler,Germany), and CMVPT30-gfp, a cell-free HCMV clinically-derived strainexpressing GFP (PT30). These viral strains were maintained as cell-freeviral stocks. In addition, the low-passage clinical isolate CI851,recovered at the Hadassah Clinical Virology Laboratory from the urine ofa congenitally-infected newborn, and propagated for 3-5 passages ascell-associated virus was used. A cell-free stock of CI851 was preparedby sonication of infected cells, followed by removal of pelletedcellular debris. Virus titers of the cleared supernatants weredetermined by the standard plaque assay on HFF.

Preparation and Infection of Decidual Organ Cultures

Decidual tissues from women undergoing first-trimester electivepregnancy terminations were obtained by deep scraping to obtain maternaltissue from the basal plate and placental bed encompassing the deciduawith interstitial trophoblastic invasion. The study was approved by theHadassah Medical Center Institutional Review Board, and performedaccording to the Declaration of Helsinki, Good Clinical Practiceguidelines, and the Human-Experimentation Guidelines of the IsraeliMinistry of Health. All donors gave written informed consent. Tissues,delivered within 4 hours after surgery, were kept on ice untilsectioning. For preparation of decidual organ cultures, tissues werewashed with phosphate buffered saline (PBS), cut by a microtome (TissueSectioner, TC-2, Sorvall Corp.) into thin slices (250 μm thickness)encompassing ˜10 cell layers, and incubated in DMEM with 25% Ham's F12,10% fetal bovine serum, 5 mM HEPES, 2 mM glutamine, 100 IU/mlpenicillin, 100 μg/ml streptomycin (Biological industries, Beit Haemek,Israel), and 0.25 μg/ml fungizone in 37° C., 5% CO₂.

For infection of decidual organ cultures, the tissues were placed in48-well plates (˜5 slices/well to maintain optimal viability)immediately after the sectioning and inoculated with the indicated virus(10⁴ plaque forming units/well, unless indicated otherwise) for 12 hoursto allow effective viral adsorption. Following viral adsorption, thecultures were washed extensively and further incubated for the durationof the experiment with replacement of the culture medium every 2-3 days.

Tissue Viability Monitoring

Mitochondrial dehydrogenase enzyme (MTT) assay: Tissue slices wereincubated with the MTT substrate(3-[4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide]) (Sigma,Israel) for 1 hour at 37° C. and then washed in PBS, followed byaddition of 100% ethanol to dissolve the product colored crystals. Theabsorbance of four replicate samples was read using an ELISA platereader (Organon Teknika, the Netherlands) at a wavelength of 540 nm inreference to 650 nm. The viability was determined by normalization ofthe absorbance values for the protein content of each extract as testedby the Bradford assay (Kolodkin-Gal et al., 2008, J. Virol., 82,999-1010).

Glucose consumption assay: Glucose levels in the medium of the incubatedtissues were monitored after 48 hours of culture by the Accu-check™blood-sugar sensing device (Roche, Germany).

Histological and Immunohistochemistry Analysis

Decidual tissues were fixed in 37% formalin, embedded in paraffin, andcut into 5 μm sections. The sections were deparaffinized in xylene,rehydrated, and stained with hematoxylin and eosin (H&E).

For immunohistochemical detection of HCMV antigens, tissue sections wereplaced in 0.01M citrate buffer and warmed in a water bath to 90° C. for15 minutes, allowed to cool to room temperature, followed by incubationwith primary mouse monoclonal antibodies (mAbs) against HCMV diluted inCAS-block (Zymed Laboratories, CA, USA); immediate early (IE), pp65, orgB antigens (1:1000 dilution; Virusys Corporation, Taneytown, Md., USA)or CAS-Block containing no 1^(st) antibody to serve as a negativecontrol. Sections were then washed and incubated with HRP-conjugatedgoat anti-mouse secondary antibody (Biocare Medical, CA, USA). Thesections were washed again, and HCMV antigens were detected by the HRPsubstrate 3,3′Diaminobenzidine (DAB), followed by counterstaining withhematoxylin.

Immunofluorescence

Tissue specimens for immunofluorescence staining were fixed in 4%paraformaldehyde, embedded in OCT, flash frozen in liquid nitrogen andcut into 10 μm sections. Frozen sections were treated with CAS-Block inorder to avoid nonspecific antibody binding, and incubated withCAS-Block only or CAS-Block containing the following antibodies forspecific cell markers: mAbs against cytokeratin 7 (1:300 dilution, DakoGlostrup, Denmark) were used for the detection of CTBs; mAbs againstvimentin (1:100 dilution, Dako) were used for the detection of decidualstromal cells; mAbs against CD11c (1:50 dilution, Biolegend, CA, USA)were used for the detection of dendritic cells; mAbs against CD68 (1:200dilution, Abcam, Cambridge, UK) were used for the detection ofmacrophages, and rabbit polyclonal antibodies against von Willebrandfactor (1:800 dilution, Dako) were used for the detection of endothelialcells. Sections were washed and incubated with cy5-conjugated goatanti-mouse or cy5-conjugated goat anti-rabbit secondary antibodies(1:200 dilution, Jackson Immunoresearch, PA, USA), and mounted inVectashield mounting media with 4′,6-diamidino-2-phenylindole (DAPI)nuclear stain (Vector Laboratories, Burlingame, Calif.). Slides werevisualized using a Zeiss LSM710 Axio Observer.z1.confocal microscope,and analyzed using Zen 2009 software.

HCMV DNA and RNA Quantification

Infected decidual tissues and HFF cell cultures were washed extensivelyand stored at −70° C. along with their corresponding supernatants(harvested 2 days after last medium replacement).

DNA and RNA were extracted from the samples using the QIAamp DNA MiniKit extraction kit and RNeasy Mini Kit (QIAGEN, Hilden, Germany)respectively, according to the manufacturer's instructions. The purifiedDNA samples were subjected to a quantitative real-time PCR reaction on a7900HT Real Time PCR system (Applied Biosystems, Foster City, Calif.,USA), using primers and probes derived from the HCMV glycoprotein B (gB)as described in Boeckh et al., 2004, J. Clin. Microbiol., 42, 1142-1148.The assay demonstrated a linear quantitation over a 6-log range. Thepurified RNA samples were subjected to reverse transcription usingGoScript™ (Promega, Madison, USA), followed by quantitative real-timePCR of the late HCMV R160461 spliced mRNA as described in White et al.,2004, J. Virol., 78, 1817-1830. For comparative and kinetic analyses,the viral DNA copy number in tissues and HFF cell cultures wasnormalized by the cellular single-copy gene RNase P. RNase P wasquantified using the Taqman RNase P kit (Applied Biosystems) accordingto the manufacturer's instructions. The viral mRNA copy number wasnormalized by the cellular house keeping gene G6PD.

Antiviral Treatments and Assays

The antiviral drugs ganciclovir and acyclovir (Sigma) were used atconcentrations of 25 μM, 50 μM, 250 μM and 500 μM. The drugs were addedto the culture medium after virus adsorption.

To measure neutralization by antibodies, the indicated virus strain waspre-incubated with HCMV HIG (Megalotect; 100 mg protein/50 IU per ml;Biotest, Germany) at 1:10, 1:100, and 1:1000 dilutions for 1 hour atroom temperature, followed by inoculation of the pre-incubatedvirus-antibody mix on the tissues.

In post-adsorption treatment experiments, the same dilutions of HCMV HIGwere added to the culture medium at 24 hours after viral adsorption,following extensive washing to remove loosely bound virus.

The tissues were further incubated in the presence of the drug orantibodies for the duration of the experiment. Drugs or antibodies werere-supplemented upon medium replacements.

Antiviral drug susceptibility was assayed by determining the drugconcentration required to reduce the normalized tissue viral DNA copynumber by 50% (IC₅₀), employing at least 5 independent replicateexperiments per drug.

Results Establishment of a Decidual Organ Culture

Fresh first-trimester decidual tissues were sectioned into thin slices(250 μm thickness), to ensure nutrients accessibility. Decidual organcultures were placed in 48-well plates (˜5 slices/well) immediatelyafter sectioning, incubated in enriched DMEM and subjected to frequentmedia changes to maintain optimal viability. Decidual tissue viability,as monitored by both the MTT and glucose consumption assays, wasmaintained for at least 12 days of incubation ex-vivo. Furthermore,histological examination of sections obtained upon institution (day 0)and at 8 days of culture demonstrated preservation of typical decidualmorphological features with no visible signs of cell death (FIGS.6A-6B). Thus, the decidual explants remain viable and retain naturalmorphology over the time needed to support and monitor HCMV infectionand spread which typically occurs within 4-7 days.

HCMV Infection Kinetics in the Decidua

To evaluate the susceptibility of decidual organ cultures to HCMV,decidual cultures were infected with the cell-free clinically-derivedstrain PT30, expressing GFP (Fox-Canale et al., 2007, Virology, 369,55-68). This strain, which was shown to maintain a broad cell tropism toHFF, umbilical vein endothelial cells, and retinal epithelial cells, waschosen to represent the wide in vivo cell tropism of HCMV and providevisual monitoring of the infection.

To evaluate the histopathological features of ex-vivo infected decidua,histological sections of infected tissues were examined at 6 dpi.Histology sections of the ex-vivo infected tissues exhibited the typicalhistopathological characteristics of natural HCMV infection, with theappearance of cytomegalic cells with “owl's eye” inclusion bodies,granular cytoplasmic inclusions, and irregular hyperchromatic nuclei(FIGS. 6C-6D).

Immunohistochemical analysis of the infected sections revealed theexpression of both immediate early, and pp65 early-late viral genes(FIGS. 6E-6F), as well as gB (known to be expressed late afterinfection). All control tissues, including mock-infected sections andinfected sections reacted with secondary antibodies only, were negativeby immunohistochemical staining. These findings indicate that HCMVundergoes a full replication cycle in the infected decidua tissues.

To follow virus spread kinetics in the decidua, PT30 infected livetissues were monitored daily for GFP-expressing cells by confocalmicroscopy. As shown in FIGS. 7A-7D, GFP-expression was first detectedat 2 days post infection (dpi), appearing in individual cells. Gradualprogression of infection was noted by 3-7 dpi, along with the formationof plaque-like clusters of infected cells (FIGS. 7A-7D). This kineticspattern of organ culture infection was consistently observed in morethan 80 decidual tissues obtained from different subjects, and could besimilarly monitored following infection with the endotheloitropic strainTB40/E, expressing GFP-fused to the late structural protein pp150.

To further quantify progression of infection over time, the accumulationof viral DNA in the infected decidual cultures by real-time PCRfollowing infection (10⁴ PFU/well) with strains PT30, TB40/E, AD169, andthe low-passage clinical strain CI851 was measured. As shown in FIG. 8,there was a consistent increase in tissue-associated viral DNA with time(above the level of the remaining input DNA as detected at early timespost infection) which was demonstrated for all viral strains: A 1.3 to2-log increase in viral DNA accumulation was observed for all strainsbetween 2-9 dpi, reflecting active DNA synthesis within the infectedtissues. Moreover, a quantitative analysis of the HCMV true-late RNAR160461 demonstrated a 1.9 log rise within 7 dpi for both TB40/E andAD169. These findings, together with the spreading pattern of GFPexpression (independently demonstrated for the 2 differentGFP-expressing viral strains), and the expression of late viralproteins, support active viral replication in the decidual organcultures.

HCMV Infects a Wide Range of Cells in the Decidua

While HCMV is characterized by a broad cell tropism in vivo, in vitrostudies are generally limited to single cell-type cultures. To definethe cellular tropism of HCMV within the decidua, the types of infectedcells were identified. Decidual tissues infected by theclinically-derived strains TB40/E and PT30 (characterized by broad celltropism) and the poorly-endotheliotropic strains AD169 were examined.Frozen sections of HCMV-infected tissues were analyzed by confocalimmunofluorescence, using specific cell markers. FIG. 9 shows viralcolocalization of strain TB40/E with markers of invasivecytotrophoblasts (Cytokeratin 7), endothelial cells (von WillebrandFactor), decidual cells (Vimentin), dendritic cells (CD11c), andmacrophages (CD68). Similar cell tropism was shown for PT30, indicatingex-vivo infection of all major decidual cell types by HCMV. In parallelexperiments following infection with strain AD169, viral colocalizationonly with vimentin-positive stromal-decidual cells can be demonstrated.

Inhibition of HCMV Infection of Decidual Organ Cultures

Recent studies have suggested the potential applicability of prenatalantiviral interventions in preventing maternal fetal transmission andcongenital disease (Jacquemard et al., 2007 BJOG, 114, 1113-1121; andNigro et al., 2005, N. Engl. J. Med., 353, 1350-1362). While allcurrently available anti-HCMV drugs (i.e. ganciclovir, foscarnet, andcidofovir) are considered teratogenic, new and alternative antiviraloptions, including acyclovir and HCMV HIG, have been explored.

To assess the efficacy of the decidual organ culture for evaluatingantiviral activity, and to examine the ex-vivo effect of antiviral drugson HCMV replication in the decidua, infected decidual cultures wereincubated with different concentrations of ganciclovir and acyclovir.Decidual cultures were infected with HCMV strain TB40/E (10⁵ PFU/well)and were incubated with increasing concentrations of ganciclovir (GCV)or acyclovir (ACV). Viral DNA in the treated and untreated decidualtissue lysates was quantitated at 8 dpi and values were normalized byRNase P DNA copies.

FIG. 10 shows that both antiviral drugs inhibited HCMV replication inthe decidual cultures, as measured by dose-dependent reduction of viralDNA accumulation in the infected tissues. Ganciclovir exhibited a higherantiviral efficacy when compared to acyclovir (IC₅₀ of 1.5 μM versus18.3 μM). These findings demonstrate that ex-vivo infected decidualcultures can serve to study the effect of antiviral interventions and toassess the therapeutic efficacy of the compounds of the presentinvention.

The antiviral effect of HCMV HIG in the infected decidual cultures wasexamined Studies of the neutralization activity showed that HCMV HIGpreparation, when pre-incubated with the virus was capable ofneutralizing HCMV infection of the decidua (FIG. 11A). The calculatedHIG concentration for 50% viral neutralization was 36 μg/ml. Noantiviral effect was observed with HCMV IgG-negative serum. This findingcould correlate with the prophylactic effect of HIG in prevention ofmaternal-fetal transmission in vivo. It should be noted that theneutralizing activity of HCMV HIG in the decidual cultures was higherthan the neutralizing activity in fibroblasts culture. In comparativeexperiments, the neutralization titer of HCMV HIG was more than 10-foldlower in the decidual cultures than in HFF cell cultures. To furtherexamine the potential therapeutic effect of HIG, its antiviral activitywhen added after viral adsorption was examined At 24 hourspost-adsorption, tissues were extensively washed before the addition ofincreasing HIG dilutions to the culture media. A significantdose-dependent inhibition of HCMV replication was clearly demonstrated(FIG. 11B) with an IC₅₀ of 652 μg/ml. The inhibitory effect of HIG whenadded post-adsorption, was also evident by the reduction of spread ofplaque-like clusters at late times post-infection. In contrast, nopost-adsorption inhibitory effect was observed in HFF cell cultures.These studies reveal a combined neutralization and a post-adsorptionantiviral effect of HCMV HIG in the decidua.

Thus, active viral replication in the tissue was demonstrated by 1)gradual progression of GFP-expressing cell foci following infection withGFP-expressing HCMV strains, along with a consistent increase in viralDNA over an interval of 2-9 days post infection; 2) expression of bothimmediate-early and true-late viral RNA and proteins in the infectedorgan cultures; 3) appearance of typical histopathological features ofnatural infection; and 4) a dose-dependent inhibition of viral spreadand DNA accumulation by the antiviral DNA polymerase inhibitorganciclovir. These combined findings demonstrate the ability of theex-vivo infected decidual organ culture to address dynamic aspects ofviral tropism and spread.

A wide range of cells which are infected by HCMV clinically-derivedstrains in the decidua was identified, including invasive CTBs,endothelial cells, macrophages, stromal decidual, and dendritic cells.This finding reflects the unique multi-cell-type nature of the decidua.The infected cells in the decidua represent the two distinct pathways ofviral entry, i.e. fusion (at the cell surface) and endocytosis-mediated,as characterized in fibroblasts and in epithelial/endothelial cells,respectively. Whereas HCMV endocytosis-mediated entry has been shown torequire the viral gH/gL/UL128-131 complexes, the UL128-131 proteins arenot essential for HCMV fusion-mediated entry.

The combined virus neutralization and post-infection effect of HCMV HIG,demonstrates the capability of the ex-vivo model in the decidual organcultures to evaluate the effect of new antiviral interventions in thematernal-fetal interface. For example, the infected decidual organcultures could provide the mechanistic basis for clinical trialsaccessing prenatal prophylactic and therapeutic use of anti-HCMV drugs.The ex-vivo modeling of HCMV infection in a novel decidual organ culturerevealed a broad target-cell range with consistent cell-to-cell mode ofspread of both clinically- and laboratory-derived viral strains. Thismodel can be used to evaluate the efficacy of the compounds of thepresent invention as new, effective and non-teratogenic anti-HCMV drugs.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingcurrent knowledge, readily modify and/or adapt for various applicationssuch specific embodiments without undue experimentation and withoutdeparting from the generic concept, and, therefore, such adaptations andmodifications should and are intended to be comprehended within themeaning and range of equivalents of the disclosed embodiments. It is tobe understood that the phraseology or terminology employed herein is forthe purpose of description and not of limitation. The means, materials,and steps for carrying out various disclosed functions may take avariety of alternative forms without departing from the invention.

It should be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

1. A method of treating a viral infection or suppressing viral replication comprising the step of administering to a subject a pharmaceutical composition comprising a pharmaceutically acceptable carrier or excipient and a therapeutically effective amount of a compound having anti-viral activity represented by the structure of formula I:

or a salt or a solvate thereof, wherein Y represents a group —NR¹R²; wherein R¹ and R² together with the interjacent nitrogen atom represent a non-aromatic heterocyclic group selected from the group consisting of piperazinyl, morpholinyl, thiomorpholinyl, and morpholinosulphonyl, and wherein said viral infection or replication is a cytomegalovirus infection or replication.
 2. The method of claim 1, wherein said non-aromatic heterocyclic group is substituted.
 3. The method of claim 1, wherein said compound is represented by the structure of formula VIII:


4. The method of claim 1, wherein said viral infection or replication is a human cytomegalovirus infection or replication.
 5. The method of claim 1, wherein the pharmaceutical composition in the form selected from the group consisting of tablets, pills, capsules, pellets, granules, powders, lozenges, sachets, cachets, elixirs, suspensions, dispersions, emulsions, solutions, syrups, aerosols, ointments, soft and hard gelatin capsules, suppositories, sterile injectable solutions, and sterile packaged powders.
 6. The method of claim 1, wherein the step of administering is performed via a route selected from the group consisting of oral, rectal, intramuscular, subcutaneous, intravenous, inrtaperitoneal, intranasal, intraarterial, intravesicle, intraocular, transdermal and topical.
 7. The method of claim 1, further comprising co-administering said compound with at least one other anti-viral drug.
 8. The method of claim 7, wherein the at least one other anti-viral drug is selected from the group consisting of ganciclovir, valganciclovir, foscarnet, cidofovir, acyclovir and valacyclovir.
 9. The method of claim 7, wherein said compound and the at least one other anti-viral drug are administered in a regimen selected from the group consisting of a single combined composition, separate individual compositions administered substantially at the same time, and separate individual compositions administered under separate schedules. 